Novak Corp. just began business and made the following four inventory purchases in June: June 1 183 units $1270 June 10 244 units 1900 June 15 244 units 2050 June 28 183 units 1610 $6830 A physical count of merchandise inventory (rounded to whole dollar) on June 30 reveals that there are 260 units on hand. The inventory method which results in the highest gross profit for June is